New research published this week in the journal Science finds an increase in small earthquakes may be related to industrial wastewater being pumped into underground storage wells.
Although small earthquakes happen every day across the U.S., the numbers have been going up.
The research reveals two reasons for this: large earthquakes that occur around the globe, and activity at geothermal power plants.
Most of these little quakes in the U.S. are too small to feel. They tend to happen in “swarms.” Over the past year, geoscientists traced some of these swarms to underground faults near deep wells that are often filled with waste fluid from the oil and gas drilling boom.
Nicholas van der Elst, a geophysicist with Columbia University’s Lamont Doherty Earth Observatory, says there are lots of small faults all over the country. The injection of fluids migrates in and around the fault itself, “and kind of pushes outward on the fault walls and makes it easier for the fault to slip,” he says.
The wastewater “loads up” these faults with tension until, at some point, they slip and the earth moves.
According to the Environmental Protection Agency there currently seven active deep injection wells for oil and gas waste in Pennsylvania and four pending applications.
Nationwide there are about 144,000 of these types of oil and gas waste disposal wells. Most are located in Texas, California, Oklahoma, and Kansas.
Collectively they receive over 2 billion gallons of brine every day.